1. Field of the Invention
The present invention relates to electronic memory devices such as DRAMs (Dynamic Random Access Memories, dynamic read/write memories), and relates particularly to a method and apparatus for refreshing information stored in memory cells in a memory cell array.
2. Description of the Prior Art
The present invention relates specifically to an electronic memory device for storing data having a memory cell array, for example arranged in memory banks, which has memory cells and having word lines and bit lines for addressing/reading the memory cells in the memory cell array, with information stored in the memory cells in the memory cell array being refreshed by applying a predetermined activation potential at a predetermined refresh rate to the word lines.
In designing electronic memory devices which have individual memory cells for storing electrical charge, miniaturization of the relevant memory devices gives rise to problems in maintaining the charge or the stored information in the memory device, in particular.
“Retention problems”, i.e. problems in retaining the stored information or the stored electrical charge, increase significantly when future production technologies such as 90-nanometer technology or 70-nanometer technology are used. In this context, the drawback arises that the memory cells formed from trench capacitors, for example, need to be produced in ever narrower and deeper form, which gives rise to leakage paths which result in a reduction in the electrical charge stored in the memory cells.
To solve this problem, the prior art has proposed numerous methods for process optimization in the manufacture of the electronic memory device. However, such methods entail considerable drawbacks with regard to yield, development time and development costs. In addition, a loss of speed for the data processing by the electronic memory apparatus may disadvantageously arise at low temperatures.